During engine operation small amounts of combustion gases may leak past piston rings into the crankcase during combustion operation. These gases are commonly referred to as blow-by gases. Blow-by gases may significantly contribute to engine emissions when left unmitigated. Therefore, positive crankcase ventilation (PCV) systems have been developed to decrease blow-by gas emissions, thereby reducing vehicle emissions. The PCV systems are typically configured to draw air from the crankcase into the intake system, and subsequently the cylinders, thereby creating a closed loop for the blow-by gases. As a result, blow-by gas emissions are reduced, thereby reducing the engine's environmental impact. However, the blow-by gases may also contain oil droplets or vapor which may degrade combustion operation when flowed into the cylinders from the PCV system. When oil droplets are flowed into the cylinders from the intake system, engine emissions are increased and engine power output is decreased. Therefore, oil separators have been developed to remove oil from the blow-by gases flowed into the intake system from a PCV outlet.
U.S. Pat. No. 8,495,993 discloses an oil separator mechanism positioned between a first and second cylinder blocks in a valley. The oil separator mechanism includes a baffle defining the boundary between a contaminated air chamber and a clean air chamber. The baffle is configured to separate oil from the gases flowing through the separator. The Inventors have recognized several drawbacks with the oil separator disclosed in U.S. Pat. No. 8,495,993. For example, the baffle disclosed in U.S. Pat. No. 8,495,993 has a large surface area, thereby decreasing the compactness of the oil separator and more generally the PCV system. Moreover, the geometry of the baffle and an inlet conduit of the separator also increase losses within the PCV system. As a result, a higher vacuum is needed in the intake system to draw the blow-by gas from the crankcase, limiting the periods of PCV operation. Consequently, engine emissions are increased.
As such in one approach, an oil separator in a positive crankcase ventilation (PCV) system is provided. The oil separator includes an oil separation conduit in fluidic communication with an intake conduit and an oil reservoir and an entry conduit including an entry conduit orifice arranged at an angle of between 80 and 100 degrees with regard to the oil separation conduit, the entry conduit orifice opening into the separation conduit at a point between the separation conduit outlet and the separation conduit inlet.
When the conduits in the oil separator are arranged in this way, oil droplets in the crankcase gases flowing therethrough contact a wall of the oil separation conduit to substantially reduce the likelihood (e.g., inhibits) of oil droplets flowing downstream into an exit port of the oil separator. Oil is therefore collected in the oil separation conduit. It will be appreciated that arranging of the oil separation conduit and entry conduit in this way increases the amount of oil which may be separated from the crankcase gas when compared to prior oil separators. Additionally, the arrangement of the oil separation conduit and the entry conduit in this way enables oil to be removed from crankcase gases flowing threrethrough via a compact device. As a result, compactness of the PCV system may be increased, if desired, while enabling a greater amount of oil to be removed from the crankcase gases. Moreover, the losses in the oil separator are also decreased, due to the configuration of the oil separation conduit and entry conduit, when compared to previous oil separators.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.